AmphibiaWeb - Callulina stanleyi


(Translations may not be accurate.)

Callulina stanleyi Loader, Gower, Ngalason & Menegon, 2010
Stanley's Warty Frog
family: Brevicipitidae
genus: Callulina
Species Description: Loader SP, Gower DJ, Ngalason W, Menegon M 2010 Three new species of Callulina (Amphibia: Anura: Brevicipitidae) highlight local endemism and conservation plight of Africa's Eastern Arc forests. Zool J Linn Soc 160: 496-514.
Callulina stanleyi
© 2010 Michele Menegon (1 of 1)
Conservation Status (definitions)
IUCN Red List Status Account Critically Endangered (CR)
National Status None
Regional Status None


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Callulina stanleyi is one of the medium to large species of Callulina frog species. More specifically, the maximum snout to the urostyle length is around 42.5 mm and the snout-vent to tibia ratio ranges from around 0.33 - 0.39. It has a larger, more robust head to go along with its robust body. On the head, the tympanum is present; however, it can be difficult to detect due to the bumpy skin. The skin is granular and warty. In terms of hand proportions, when the tips of the phalanges are spread apart, the ratio of widths of the first subarticular arch to the distal phalanx ranges from 0.8 - 1.0. The digits have truncated tips. In the holotype, the order of finger length from shortest to longest is: first finger, second and fourth fingers are equal, and then the third finger. A noteworthy feature on their hands is the prominent subarticular tubercles of the hands. When looking at the feet of the holotype, the toe tips were a tad expanded to the side and were smooth on the underside. The order of toe length from shortest to longest is: first and second toe are equal, then the third and fifth toe are equal, and the fourth toe is the longest. Similar to the hands, the subarticular tubercles of the feet are also prominent (Loader et al. 2010). Callulina stanleyi does not have large glands in their limbs (Menegon et al. 2011).

Members of the Callulina genus are easily characterized by the appearance of granular warty skin and the truncation of toes and fingertips. Most of the morphological distinctions that can be made for C. stanleyi is in the hand morphology. Unlike C. kreffti, C. stanleyi has less expansion in the third finger. However, C. stanleyi still has expanded fingertips and toe tips, which can be distinguished from species such as C. dawida that do not have this feature. The presence of a tympanum can distinguish it from other Callulina species that lack a tympanum such as C. laphami and C. shengena. Callulina kisiwamsitu is the most morphologically similar, but can be distinguished from C. stanleyi through the use of genetics, their calls, and geographic location in which they are found (Loader et al. 2010). Lastly, C. stanleyi does not have large glands in their limbs, as seen in C. meteora (Menegon et al. 2011).

Callulina stanleyi coloration in life is characterized by a brown body with an irregular, mottled appearance with white warts running along the sides of the body. The underside of the body has a light cream color. The transition from the darker brown to the lighter cream appears blended as the darker brown marbling can be seen on the edges of this cream color. The subarticular tubercles in both the hands and feet are bluish grey. The eyes are a range of orange to red in color (Loader et al. 2010).

Variation can be seen in the degree of darkness and degree of mottling of the brown coloration. Furthermore, the degree to which the tympanum is obscured also varies from individual to individual (Loader et al. 2010).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Tanzania, United Republic of

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Callulina stanleyi are found in the Eastern Arc Mountains of Tanzania and Kenya. The forests that C. stanleyi are found in are submontane forests. Callulina stanleyi can be found in microhabitats such as rotten logs and in low bushes. They establish themselves along forest roads and dense parts of the forest. Most C. stanleyi are in cooler, high-altitude areas between 1200 - 1300 m and have an estimated extent of occurrence less than or equal to 9.7 km2 (Loader et al. 2010).

Life History, Abundance, Activity, and Special Behaviors
Callulina stanleyi can be found in microhabitats such as rotten logs and low bushes at night (Loader et al. 2010).

General characteristics of Callulina species are that they are terrestrial, arboreal, breed during the dry season, which is from June to October. Around July, males begin to advertise themselves using a distinct mating call that is only known in the South Pare Mountains (Malzona 2008).

Male C. stanleyi call at night from low branches of bushes or trees. This call has 7 to 9 sharp trills per call, each of which lasts 1 to 2 seconds. The frequency of these calls can reach a maximum of 1720 Hz. The pulse duration for each group lasted around 25 ms, while the intergroup pulse duration lasted around 116 ms (Loader et al. 2010).

In general, female Callulina lay eggs and their offspring undergo direct development. This genus exhibits parental care, as females brood their eggs from when they are deposited in September to when they begin hatching in November. These eggs are cared for in a nested structure in the leaf litter. Although abundant information does not exist on average clutch size, Malonza (2008) observed a female Callulina with 30 to 40 eggs in her clutch that were approximately 2 mm in diameter around the time of deposition in September. The eggs are composed of yolk surrounded by jelly capsules. Offspring develop relatively fast and will reach reproductive age at around 8 months of age (Malonza 2008).

Trends and Threats
The genus Callulina is particularly under threat due to only appearing in highly fragmented regions, being restricted within certain altitude ranges, and dwindling forest habitats (Malonza 2008). Specifically, the population trend of C. stanleyi is unknown. The top environmental threats of C. stanleyi include residential and commercial development, agriculture and aquaculture, and biological resource use. In the submontane forests of the South Pare Mountains, where this species is located, there has been a significant decline over the years. Due to the ideal conditions for human inhabitation and agriculture, the outskirts of the reserves have been lost for human use. Thus, there is only a small range by which C. stanleyi is distributed, putting them at a higher risk for any environmental threats. Furthermore, there is an increasing threat of future agriculture-related encroachment on the remaining part of the reserve, as there is already a limited amount of space for this species. There is also additional habitat loss from human-related forest degradation and logging activities in the Chome Forest Reserve (IUCN 2020).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Intensified agriculture or grazing


Maximum likelihood, Maximum Parsimony, and Bayesian Inference of 12S, 16S and cytochrome b showed that the most closely related species to C. stanleyi is C. kisiwamsitu. The next most closely related species is C. kreffti followed by C. dawida. The clade composed of these species is sister to the clade composed of C. laphami, and C. shengena (Loader et al. 2010).

Callulina stanleyi is named after William T. Stanley, who made various contributions to the biological diversity of the Eastern Arc Mountains (Loader et al. 2010).


IUCN SSC Amphibian Specialist Group, 2020. “Callulina stanleyi (amended version of 2012 assessment).” The IUCN Red List of Threatened Species 2020: e.T193429A176116120. Downloaded on 21 January 2021.

Loader, S. P., Gower, D. J., Ngalason, W., and Menegon, M. (2010). ''Three new species of Callulina (Amphibia: Anura: Brevicipitidae) highlight local endemism and conservation plight of Africa's Eastern Arc forests.'' Zoological Journal of the Linnean Society, 160, 496-514.

Malonza, K. P. W. (2008). "Amphibian Biodiversity in Taita Hills, Kenya." University of Mainz, Mainz, Germany

Menegon, M., Gower, D. J., Loader, S. P. (2011). “A remarkable new species of Callulina (Amphibia: Anura: Brevicipitidae) with massive, boldly coloured limb glands.” Zootaxa 3095,15-26.

Originally submitted by: Elise Israel, Alice Kim, Raquel Ponce (2021-08-12)
Description by: Elise Israel, Alice Kim, Raquel Ponce (updated 2021-08-12)
Distribution by: Elise Israel, Alice Kim, Raquel Ponce (updated 2021-08-12)
Life history by: Elise Israel, Alice Kim, Raquel Ponce (updated 2021-08-12)
Trends and threats by: Elise Israel, Alice Kim, Raquel Ponce (updated 2021-08-12)
Comments by: Elise Israel, Alice Kim, Raquel Ponce (updated 2021-08-12)

Edited by: Ann T. Chang (2021-08-12)

Species Account Citation: AmphibiaWeb 2021 Callulina stanleyi: Stanley's Warty Frog <> University of California, Berkeley, CA, USA. Accessed Jul 16, 2024.

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Citation: AmphibiaWeb. 2024. <> University of California, Berkeley, CA, USA. Accessed 16 Jul 2024.

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